Cyclosporiasis cases rising: What to know

Parasite can cause watery diarrhea that lasts for weeks. Find out how it reaches food and when to call a doctor.

1:50 p.m. July 12, 2026

DUANE CROSS
MCO Publisher•Editor

At first, it can feel like an ordinary stomach bug.

The diarrhea starts. Then come the cramps, nausea, bloating, and fatigue. But instead of clearing up after a day or two, cyclosporiasis can hang on for weeks. A person may begin to feel better, only to have the symptoms return.

As of July 9, the Centers for Disease Control and Prevention had received reports of 843 confirmed cases acquired inside the United States. The cases were reported by 31 states. At least 86 people had been hospitalized. No deaths had been reported.

Those illnesses have not all been traced to a single food or a nationwide outbreak. Federal and state health officials are investigating several clusters, while other cases have not been connected to a shared source.

The Food and Drug Administration has opened several investigations, but the products responsible have not been identified.

The immediate question for anyone with fresh produce in the refrigerator is whether something needs to be thrown away.

So far, federal officials say no.

Tennessee Cases Confirmed

The CDC’s national map places Tennessee in the range of 11 to 30 confirmed, domestically acquired cases.

It is not known whether any of those cases are in Moore County.

The numbers are preliminary and may change as state health departments confirm illnesses and send additional information to the CDC. Federal officials say there can be a delay of about six weeks between the time someone becomes sick and when the case appears in the national count.

Cyclosporiasis is a reportable disease in Tennessee. Healthcare providers and laboratories are required to notify public-health officials when they identify or suspect a case.

A Parasite That Can Linger

Cyclosporiasis is an intestinal illness caused by a microscopic, one-celled parasite called Cyclospora cayetanensis.

The parasite infects the small intestine. Its most common symptom is watery diarrhea, which can be frequent and severe.

The diarrhea is often joined by stomach cramps, bloating, gas, nausea, loss of appetite, weight loss, and deep fatigue. Some patients also experience vomiting, body aches, headaches, or a low-grade fever.

Symptoms usually begin about a week after someone consumes contaminated food or water. In some cases, they can appear as early as two days after exposure or take two weeks or longer to develop.

Without treatment, the illness may last from a few days to more than a month. The stop-and-start nature of the symptoms can make it especially frustrating. A person may think the illness has passed, only to have the diarrhea and fatigue return.

Cyclosporiasis is not usually life-threatening, but persistent diarrhea can lead to dehydration. People in poor health or with weakened immune systems may be more likely to suffer a severe or prolonged illness.

How Food Becomes Contaminated

Cyclospora begins with human waste.

Humans are the only known host for the species that causes cyclosporiasis. An infected person can shed the parasite in feces, even without showing symptoms.

But Cyclospora does not usually spread directly from one person to another, unlike norovirus and some other stomach illnesses.

Once the parasite leaves the body, it must remain in the environment for at least one to two weeks before it becomes infectious. That delay makes immediate person-to-person transmission unlikely.

Health officials still do not understand every route by which the parasite enters food and water. Contamination can occur when human waste reaches irrigation or washing water, fields, equipment, packing areas, or other parts of the food-production system.

Fresh produce can be especially vulnerable because it is often eaten raw.

A contaminated herb, berry, or leafy green can move from a field to a packing facility, then through a distributor and into grocery stores or restaurant kitchens across several states before anyone realizes there is a problem.

Past U.S. outbreaks have been connected to raspberries, basil, cilantro, snow peas, and mesclun lettuce. Those earlier outbreaks do not mean any of those foods are responsible for the current cases.

Tracing the source can be difficult. People may not become sick until a week or more after eating contaminated food. By the time investigators begin asking questions, the package may be gone, leftovers may have been discarded, and the same ingredient may have appeared in several meals.

Washing Helps – But It Is Not Foolproof

Thoroughly washing fruits and vegetables remains an important food-safety step. It does not, however, guarantee that every Cyclospora parasite will be removed.

• The parasite can cling to the surface of produce or settle into small crevices. Chlorine and other common antimicrobial treatments are not considered reliably effective against it.

• Fresh produce does not need to be removed from the menu, but it should be handled carefully.

• Wash your hands with soap and water before and after preparing raw fruits and vegetables.

• Rinse produce thoroughly under running water before eating, cutting, or cooking it. Firm produce, including melons and cucumbers, should be scrubbed with a clean produce brush.

• Cut away bruised or damaged areas. Wash knives, cutting boards, countertops, and other surfaces that come into contact with raw produce.

• Cut, peeled, or cooked fruits and vegetables should be refrigerated within two hours.

• Produce labeled “prewashed” or “ready to eat” does not need to be washed again, according to the CDC.

Those steps can reduce the risk of foodborne illness, but washing may not remove every Cyclospora parasite from contaminated raw produce.

When to Call a Doctor

Persistent watery diarrhea should not be ignored, especially when it lasts several days, recurs after improvement, or is accompanied by weight loss and severe fatigue.

Anyone with those symptoms should contact a healthcare provider and mention Cyclospora.

Diagnosis requires testing a stool sample, and the test needed to detect the parasite may not be included in a routine stool examination. In some cases, several samples collected on different days may be needed.

The standard treatment is the prescription antibiotic trimethoprim-sulfamethoxazole, commonly called TMP-SMX and sold under brand names including Bactrim and Septra.

People who are allergic to sulfa drugs should speak with their healthcare providers. The CDC says there are no highly effective alternative antibiotic treatments currently available.

Rest and fluids are also important. Anyone who cannot keep fluids down, feels faint or confused, urinates very little, or shows other signs of serious dehydration should seek prompt medical care.

The Bottom Line

The CDC’s national map places Tennessee in the range of 11 to 30 confirmed cases. It is not known whether any of those illnesses involve Moore County residents.

Investigators have not identified one food responsible for all 843 confirmed cases nationwide. The total includes several clusters under investigation, as well as other illnesses not linked to a shared source.

There is no specific food to throw away and no blanket warning to avoid fresh produce.

Watery diarrhea that hangs on, eases, and then comes back is worth a call to the doctor – and a question about testing for Cyclospora.